close all
theta=pi/4;
v=[cos(theta) sin(theta)];
o=[0 0];

ceuArrow(o,v,'b',2)
text(v(1)+0.1,v(2)+0.1,'v','FontSize',14)
axis([-1.5 1.5 -1.5 1.5])
axis square
grid on
xlabel('x_1')
ylabel('x_2')

theta=0:1e-3:2*pi;
plot(cos(theta),sin(theta),'k','LineWidth',2);
theta=0:1e-3:pi/4;
plot(0.5*cos(theta),0.5*sin(theta),'k:','LineWidth',2);
text(0.55,0.25,'\theta','FontSize',14)

